'\" te
.\" Copyright (c) 2003, Sun Microsystems, Inc.
.\" All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH GLD 9F "February 15, 2020"
.SH NAME
gld, gld_mac_alloc, gld_mac_free, gld_register, gld_unregister, gld_recv,
gld_sched, gld_intr \- Generic LAN Driver service routines
.SH SYNOPSIS
.nf
#include <sys/gld.h>

\fBgld_mac_info_t *\fR\fBgld_mac_alloc\fR(\fBdev_info_t *\fR\fIdip\fR);
.fi

.LP
.nf
\fBvoid\fR \fBgld_mac_free\fR(\fBgld_mac_info_t *\fR\fImacinfo\fR);
.fi

.LP
.nf
\fBint\fR \fBgld_register\fR(\fBdev_info_t *\fR\fIdip\fR, \fBchar *\fR\fIname\fR, \fBgld_mac_info_t *\fR\fImacinfo\fR);
.fi

.LP
.nf
\fBint\fR \fBgld_unregister\fR(\fBgld_mac_info_t *\fR\fImacinfo\fR);
.fi

.LP
.nf
\fBvoid\fR \fBgld_recv\fR(\fBgld_mac_info_t *\fR\fImacinfo\fR, \fBmblk_t *\fR\fImp\fR);
.fi

.LP
.nf
\fBvoid\fR \fBgld_sched\fR(\fBgld_mac_info_t *\fR\fImacinfo\fR);
.fi

.LP
.nf
\fBuint_t\fR \fBgld_intr\fR(\fBcaddr_t);\fR
.fi

.LP
.nf
\fBvoid\fR \fBgld_linkstate\fR(\fBgld_mac_info_t *\fR\fImacinfo\fR, \fBint32_t\fR \fInewstate\fR);
.fi

.SH INTERFACE LEVEL
illumos architecture specific (illumos DDI).
.SH PARAMETERS
.ne 2
.na
\fB\fImacinfo\fR \fR
.ad
.RS 13n
Pointer to a \fBgld_mac_info\fR(9S) structure.
.RE

.sp
.ne 2
.na
\fB\fIdip\fR \fR
.ad
.RS 13n
Pointer to \fBdev_info\fR structure.
.RE

.sp
.ne 2
.na
\fB\fIname\fR \fR
.ad
.RS 13n
Device interface name.
.RE

.sp
.ne 2
.na
\fB\fImp\fR \fR
.ad
.RS 13n
Pointer to a message block containing a received packet.
.RE

.sp
.ne 2
.na
\fB\fInewstate\fR \fR
.ad
.RS 13n
Media link state.
.RE

.SH DESCRIPTION
\fBgld_mac_alloc\fR(\|) allocates a new \fBgld_mac_info\fR(9S) structure and
returns a pointer to it. Some of the GLD-private elements of the structure may
be initialized before \fBgld_mac_alloc\fR(\|) returns; all other elements are
initialized to zero. The device driver must initialize some structure members,
as described in \fBgld_mac_info\fR(9S), before passing the mac_info pointer to
\fBgld_register\fR(\|).
.sp
.LP
\fBgld_mac_free\fR(\|) frees a \fBgld_mac_info\fR(9S) structure previously
allocated by \fBgld_mac_alloc\fR(\|).
.sp
.LP
\fBgld_register\fR(\|) is called from the device driver's \fBattach\fR(9E)
routine, and is used to link the GLD-based device driver with the GLD
framework. Before calling \fBgld_register\fR(\|) the device driver's
\fBattach\fR(9E) routine must first use \fBgld_mac_alloc\fR(\|) to allocate a
\fBgld_mac_info\fR(9S) structure, and initialize several of its structure
elements. See \fBgld_mac_info\fR(9S) for more information. A successful call to
\fBgld_register\fR(\|) performs the following actions:
.RS +4
.TP
.ie t \(bu
.el o
links the device-specific driver with the GLD system;
.RE
.RS +4
.TP
.ie t \(bu
.el o
sets the device-specific driver's private data pointer (using
\fBddi_set_driver_private\fR(9F)) to point to the \fBmacinfo\fR structure;
.RE
.RS +4
.TP
.ie t \(bu
.el o
creates the minor device node.
.RE
.sp
.LP
The device interface name passed to \fBgld_register\fR(\|) must exactly match
the name of the driver module as it exists in the filesystem.
.sp
.LP
The driver's \fBattach\fR(9E) routine should return \fBDDI_SUCCESS\fR if
\fBgld_register\fR(\|) succeeds. If \fBgld_register\fR(\|) returns
\fBDDI_FAILURE\fR, the \fBattach\fR(9E) routine should deallocate any resources
it allocated before calling \fBgld_register\fR(\|) and then also return
\fBDDI_FAILURE\fR.
.sp
.LP
\fBgld_unregister\fR(\|) is called by the device driver's \fBdetach\fR(9E)
function, and if successful, performs the following tasks:
.RS +4
.TP
.ie t \(bu
.el o
ensures the device's interrupts are stopped, calling the driver's
\fBgldm_stop\fR(\|) routine if necessary;
.RE
.RS +4
.TP
.ie t \(bu
.el o
removes the minor device node;
.RE
.RS +4
.TP
.ie t \(bu
.el o
unlinks the device-specific driver from the GLD system.
.RE
.sp
.LP
If \fBgld_unregister\fR(\|) returns \fBDDI_SUCCESS\fR, the \fBdetach\fR(9E)
routine should deallocate any data structures allocated in the \fBattach\fR(9E)
routine, using \fBgld_mac_free\fR(\|) to deallocate the \fBmacinfo\fR
structure, and return \fBDDI_SUCCESS\fR. If \fBgld_unregister\fR(\|) returns
\fBDDI_FAILURE\fR, the driver's \fBdetach\fR(9E) routine must leave the device
operational and return \fBDDI_FAILURE\fR.
.sp
.LP
\fBgld_recv\fR(\|) is called by the driver's interrupt handler to pass a
received packet upstream. The driver must construct and pass a STREAMS
\fBM_DATA\fR message containing the raw packet. \fBgld_recv\fR(\|) determines
which STREAMS queues, if any, should receive a copy of the packet, duplicating
it if necessary. It then formats a \fBDL_UNITDATA_IND\fR message, if required,
and passes the data up all appropriate streams.
.sp
.LP
The driver should avoid holding mutex or other locks during the call to
\fBgld_recv\fR(\|). In particular, locks that could be taken by a transmit
thread may not be held during a call to \fBgld_recv\fR(\|): the interrupt
thread that calls \fBgld_recv\fR(\|) may in some cases carry out processing
that includes sending an outgoing packet, resulting in a call to the driver's
\fBgldm_send\fR(\|) routine. If the \fBgldm_send\fR(\|) routine were to try to
acquire a mutex being held by the \fBgldm_intr\fR(\|) routine at the time it
calls \fBgld_recv\fR(\|), this could result in a panic due to recursive mutex
entry.
.sp
.LP
\fBgld_sched\fR(\|) is called by the device driver to reschedule stalled
outbound packets. Whenever the driver's \fBgldm_send\fR(\|) routine has
returned \fBGLD_NORESOURCES\fR, the driver must later call \fBgld_sched\fR(\|)
to inform the GLD framework that it should retry the packets that previously
could not be sent. \fBgld_sched\fR(\|) should be called as soon as possible
after resources are again available, to ensure that GLD resumes passing
outbound packets to the driver's \fBgldm_send\fR(\|) routine in a timely way.
(If the driver's \fBgldm_stop\fR(\|) routine is called, the driver is absolved
from this obligation until it later again returns \fBGLD_NORESOURCES\fR from
its \fBgldm_send\fR(\|) routine; however, extra calls to \fBgld_sched\fR(\|)
will not cause incorrect operation.)
.sp
.LP
\fBgld_intr\fR(\|) is GLD's main interrupt handler. Normally it is specified as
the interrupt routine in the device driver's call to \fBddi_add_intr\fR(9F).
The argument to the interrupt handler (specified as \fIint_handler_arg\fR in
the call to \fBddi_add_intr\fR(9F)) must be a pointer to the
\fBgld_mac_info\fR(9S) structure. \fBgld_intr\fR(\|) will, when appropriate,
call the device driver's \fBgldm_intr\fR(\|) function, passing that pointer to
the \fBgld_mac_info\fR(9S) structure. However, if the driver uses a high-level
interrupt, it must provide its own high-level interrupt handler, and trigger a
soft interrupt from within that. In this case, \fBgld_intr\fR(\|) may be
specified as the soft interrupt handler in the call to
\fBddi_add_softintr\fR(\|).
.sp
.LP
\fBgld_linkstate()\fR is called by the device driver to notify GLD of changes
in the media link state. The newstate argument should be set to one of the
following:
.sp
.ne 2
.na
\fB\fBGLD_LINKSTATE_DOWN\fR \fR
.ad
.RS 26n
The media link is unavailable.
.RE

.sp
.ne 2
.na
\fB\fBGLD_LINKSTATE_UP\fR \fR
.ad
.RS 26n
The media link is unavailable.
.RE

.sp
.ne 2
.na
\fB\fBGLD_LINKSTATE_UNKNOWN\fR \fR
.ad
.RS 26n
The status of the media link is unknown.
.RE

.sp
.LP
If a driver calls \fBgld_linkstate()\fR, it must also set the GLD_CAP_LINKSTATE
bit in the gldm_capabilities field of the \fBgld_mac_info\fR(9S) structure.
.SH RETURN VALUES
\fBgld_mac_alloc\fR(\|) returns a pointer to a new \fBgld_mac_info\fR(9S)
structure.
.sp
.LP
\fBgld_register\fR(\|) and \fBgld_unregister\fR(\|) return:
.sp
.ne 2
.na
\fB\fBDDI_SUCCESS\fR \fR
.ad
.RS 16n
on success.
.RE

.sp
.ne 2
.na
\fB\fBDDI_FAILURE\fR \fR
.ad
.RS 16n
on failure.
.RE

.sp
.LP
\fBgld_intr\fR(\|) returns a value appropriate for an interrupt handler.
.SH SEE ALSO
.BR gld (4D),
.BR dlpi (4P),
.BR attach (9E),
.BR gld (9E),
.BR ddi_add_intr (9F),
.BR gld_mac_info (9S),
.BR gld_stats (9S)
.sp
.LP
\fIWriting Device Drivers\fR
